Composition for the cosmetic and/or pharmaceutical treatment of the upper layers of the epidermis by topical application to the skin, and corresponding preparation process

ABSTRACT

Composition comprising biodegradable nanoparticles encapsulating oils which are active and/or which contain an active ingredient having a cosmetic and/or pharmaceutical action in the upper layers of the epidermis. The nanoparticles are preferably prepared from a polymer of (C 2 -C 12 ) alkyl cyanoacrylate.

[0001] The present invention relates to a composition for the cosmeticand/or pharmaceutical treatment of the upper layers of the epidermis, bytopical application of the said composition to the skin, and apreparation process for obtaining it.

[0002] It is well known in cosmetics and/or in pharmacy to apply to theskin oils which are active and/or which contain an active ingredient.These oils are used as they are or, more often, in the form of awater-in-oil or oil-in-water emulsion. These oils are known to have anaction on the surface of the skin, but also in the upper layers of theepidermis, since they pass through the stratum corneum, the cosmeticand/or pharmaceutical action of the oils generally increasing inefficacy with an increase in the proportion of oil penetrating into theupper layers of the epidermis.

[0003] Moreover, nanoparticles are known: this name is used to denotecolloidal particles of the order of 10 to 1,000 nm in size consisting ofpolymeric materials, in which an active principle is trapped,encapsulated and/or adsorbed (see J. KREUTER, J. MICROENCAPSULATION1988, Vol. 5, pages 115-127). The term nanoparticles can be used todenote nanospheres and nanocapsules: a nanosphere constitutes a poroussolid polymer matrix on which the active ingredient is adsorbed; ananocapsule is a polymer membrane surrounding a core consisting of theactive principle. For the remainder of the description and in theclaims, the scope of the term “nanoparticles” will be strictly limitedto nanocapsules defined above. Among polymers which may be used for themanufacture of nanoparticles, biodegradable materials are preferablyselected in order to enable the said nanoparticles to be usedtherapeutically. It is known that cyanoacrylates, and especiallypolyalkyl cyanoacrylates, enable biodegradable nanoparticles to beobtained; the preparation of nanoparticles from cyanoacrylates isdescribed in EP-B-0,007,895 and EP-B-0,064,967.

[0004] The use of biodegradable nanoparticles encapsulating biologicallyactive compounds has been proposed in many therapeutic applications formany active principles, such as antimitotic or antineoplasticsubstances, antibiotics, hormonal substances, insulin, heparin orbiological products such as proteins, antigens or the constituents ofviruses, bacteria or cells. It has hence already been proposed toadminister nanoparticles encapsulating active principles orally,subcutaneously, intradermally, intramuscularly, intravenously and byapplication to the eye (see EP-B-0,007,895, EP-B-0,064,967,FR-B-2,604,903, DE-A-3,722,837, DE-A-3,341,001 and FR-B-2,304,326).

[0005] In FR-A-2,515,960, nanoparticles of cyanoacrylate encapsulatingan oil or an active substance dispersed in an oil have been described,and it is specified that these nanoparticles can be administered orally,subcutaneously, intradermally, intramuscularly or intravenously. Inaddition, in this document, the use of nanoparticles for encapsulatingperfumes has been described, the encapsulated perfumes having theadvantage of causing the perfume odour to persist longer afterapplication than in the case where the perfume is applied to the skinwithout encapsulation; encapsulation hence has a delay action on theperfume. In addition, in this case, the desired action of the perfumetakes place at the surface of the skin, and the persistence of the odouris completely independent of the fate of the fraction of thenanoparticles which might possibly pass through the stratum corneum.This topical application hence provides no information as to thepossible capacity of the nanoparticles to pass through the stratumcorneum and to be degraded in the upper layers of the epidermis; itleads, on the contrary, to the prediction that the nanoparticles wouldremain predominantly at the surface of the skin, since they permitrelease of the perfume.

[0006] According to the present application, it was found that, bycutaneous topical application of a composition comprising biodegradablenanoparticles encapsulating oils which are active and/or which containan active ingredient, an especially effective cosmetic and/orpharmaceutical action was obtained.

[0007] The improvement in the cosmetic and/or pharmaceutical efficacy ofthe oils as a result of encapsulation in nanoparticles could in no waybe foreseen; it was not obvious, in effect, on the one hand that thenanoparticles would pass through the stratum corneum more readily thanthe unencapsulated oil, whether the latter is in the form of awater-in-oil or oil-in-water emulsion, and on the other hand that thesenanoparticles would be biodegraded in the upper layers of the epidermis.It was known, admittedly, that the proposed forms for administration inthe human body, especially by injection, lead to biodegradation of thenanoparticles in the different tissue regions in which they areintroduced. However, it is well known that different tissues havedifferent constitutions and contain different enzymes; in particular, itis well known that the connective tissue of muscle, dermis and the deeplayers of the skin, where the nanoparticles had previously beenintroduced by injection, have a very different biochemical constitutionfrom that of the upper layers of the epidermis (see, for example,British Journal of Dermatology (1976) 94, 443).

[0008] Hence, nothing enabled those skilled in the art to anticipatethat the nanoparticles were, on the one hand capable of passing throughthe stratum corneum in significant amounts, and on the other handcapable of releasing the active ingredient very rapidly into the upperlayers of the epidermis.

[0009] According to the present invention, it was found, in addition,that the encapsulation of an active oil (or one containing an activeingredient) in nanoparticles produced, surprisingly, an immediate actionof the composition. The delay effect reported for the perfumingcompositions applied topically in the document FR-A-2,515,960 citedabove led those skilled in the art to anticipate that a topicalapplication, assuming it to be capable of having an effect, could haveonly a delayed action. The invention hence proposes a composition whoseproperties are unexpected. Moreover, these properties are especiallywell suited to topical administration, as was shown in a comparative invitro study of percutaneous absorption.

[0010] The subject of the present invention is consequently acomposition for the cosmetic and/or pharmaceutical treatment of theupper layers of the epidermis, by topical application to the skin,characterised in that it comprises, in a suitable vehicle, biodegradablepolymer nanoparticles encapsulating at least one active ingredient inthe form of an oil and/or at least one active ingredient contained in aninactive carrier oil or an active oil, the active ingredient beingselected from those having a cosmetic and/or pharmaceutical action.

[0011] The nanoparticles used are preferably between 10 and 1000 nm, andmore especially between 50 and 500 nm, in size.

[0012] The weight of the nanoparticles loaded with at least one activeingredient advantageously constitutes from 0.1% to 20% of the totalweight of the composition, and preferably from 0.5 to 5% by weight.

[0013] The polymers constituting the biodegradable nanoparticles can bepolymers of C₂-C₁₂, and especially C₂-C₆, alkyl cyanoacrylate; the alkylradical is preferably selected from the group composed of ethyl,n-butyl, hexyl, isobutyl and isohexyl radicals. The biodegradablepolymers may also be taken from the group composed of poly-L-lactides,poly-DL-lactides, polyglycolides, polycaprolactones, polymers of3-hydroxybutyric acid and the corresponding copolymers, such ascopoly(DL-lactides/glycolides), copoly(glycolides/caprocolatones) andthe like.

[0014] The use of nanoparticles obtained from poly-L-lactides,poly-DL-lactides and copoly(DL-lactides/glycolides) is especiallyadvantageous, since the products of enzymatic or chemical biodegradationof these nanoparticles can themselves have cosmetic effects: thus,lactic acid exhibits humectant and plasticising properties; and glycolicacid exhibits depigmenting and/or biostimulatory properties.

[0015] The active ingredients in the form of an oil (or active oils) arepreferably selected from the group composed of α-tocopherol,α-tocopherol acetate, triglycerides rich in linoleic and/or linolenicacid(s), pentaerythritol tetra(2-ethylhexanoate), clofibrate, tocopherollinoleate, fish oil, hazelnut oil, bisabolol, farnesol, farnesylacetate, ethyl linoleate and ethylhexyl para-methoxycinnamate.

[0016] The inactive carrier oils are preferably selected from the groupcomposed of triglycerides, simple or modified, especially byoxyethylenation, volatile silicone oils and mixtures thereof.

[0017] To obtain the loaded nanoparticles used in the compositionaccording to the invention it is possible either to take an active oil,or to introduce into an active oil or into a carrier oil which is initself inactive, any active ingredient capable of having a cosmetic ortherapeutic activity. These active ingredients can be, inter alia,emollients, humectants, free radical-inhibiting agents,anti-inflammatories, vitamins, depigmenting agents, anti-acne agents,antiseborrhoeics, keratolytics, slimming agents, skin colouring agentsand sunscreen agents, and in particular linoleic acid, retinol, retinoicacid, ascorbic acid alkyl esters, polyunsaturated fatty acids, nicotinicesters, tocopherol nicotinate, unsaponifiables of rice, soybean or shea,ceramides, hydroxy acids such as glycolic acid, selenium derivatives,antioxidants, β-carotene, γ-orizanol and stearyl glycerate.

[0018] The active ingredient is preferably an oleophilic activeingredient in the form of a solution in the oil. However, it can also bein the form of a dispersion, suspension or emulsion.

[0019] In the nanoparticles, the weight ratio of the biodegradablepolymer of the nanoparticles to the active oily phase is preferablybetween 0.05 and 0.5, and in particular in the region of 0.2.

[0020] The compositions according to the invention can take the form ofa physiological fluid, a lotion, an aqueous, aqueous-alcoholic or oilygel or a water-in-oil or oil-in-water emulsion, or alternatively ofaqueous dispersions of vesicles in which the constituent lipids areionic or nonionic lipids or a mixture of ionic and nonionic lipids, withor without an oily phase. Their use to constitute physiological fluidsis especially advantageous: in effect, this type of product requires theintroduction of a large amount of emulsifier in the case where it isdesired to introduce unencapsulated oily active ingredients into them,and it is well known that emulsifiers have the effect of irritating theskin and are not compatible with all active ingredients.

[0021] The compositions can contain, in addition to the nanoparticles,known cosmetically and/or pharmaceutically acceptable adjuvants, such asfats, vaseline, preservatives, thickening agents, colourings andperfumes.

[0022] When a polymer of (C₂-C₁₂) alkyl cyanoacrylate is used to obtainthe nanoparticles of the composition, an interfacial polymerisation of amicroemulsion of oil in an aqeuous-alcoholic medium is performed, asdescribed, for example, in FR-A-2,515,960, by injecting, into an aqeuousphase containing or otherwise one surfactant, a mixture consisting ofthe oil(s) to be encapsulated, at least one (C₂-C₁₂) alkyl cyanoacrylateand at least one solvent which can contain one surfactant, thenevaporating off the solvent and optionally concentrating the aqueousdispersion of nanoparticles obtained. The solvent used is, more oftenthan not, a C₂-C₄ lower alcohol, especially ethanol, propanol,isopropanol or a mixture of these alcohols, or alternatively acetone; itcan optionally contain one surfactant.

[0023] It is also possible to use the process for manufacturingnanoparticles described in European Patent Application No. 0,274,961. Inthis case, the nanoparticles are obtained by precipitation of thepolymer around a dispersion of oily droplets, by injecting, into anaqueous phase containing or otherwise one surfactant, a mixtureconsisting of the oil(s) to be encapsulated, at least one polymer and atleast one solvent containing or otherwise one surfactant, and thenevaporating off the solvent.

[0024] Other processes may also be used.

[0025] The surfactant optionally used in the preparation process canconsist of at least one nonionic surfactant, more especially selectedfrom the condensates of glycerol, ethylene oxide and propylene oxide, orof at least one ionic surfactant which can, in particular, be taken fromthe phospholipid group, such as lecithin, or alternatively of a mixtureof at least one surfactant of each of these two categories. Thissurfactant promotes the formation of the microemulsion of oil, andprevents coalescence of the nanoparticles within the reaction mixture.The weight ratio of the surfactant used on the one hand, to thematerials constituting the nanoparticles loaded with activeingredient(s) on the other hand, is advantageously between 0.01 and 0.5,and preferably in the region of 0.2.

[0026] When a surfactant used during the process for manufacturing thenanoparticles is in itself capable of forming vesicles consisting oflipid lamellae encapsulating a closed space, the said surfactant behavesin a fundamentally different way according to whether it is introducedinto the aqeuous phase or into the solvent phase. If the surfactant isin the aqueous phase, it has a tendency, at least partially, to formvesicles. If, on the other hand, the surfactant is in the solvent phase,it has a tendency, at least partially, to form one or more lipidlamellae, each consisting of a molecular bilayer, around the polymermembrane of each nanoparticle.

[0027] In the case where the oil to be encapsulated is aself-emulsifying oil, selected, for example, from oxyethylenatedtriglycerides, it is not necessary to use a surfactant.

[0028] The aqueous dispersion of nanoparticles obtained may be used asit is. It can also be lyophilised, in particular in the presence ofanticaking additives such as silicas, sugars, salts, proteins, peptidesand amino acids. The lyophilisates have the advantage of enablinganhydrous cosmetic compositions to be prepared. If the nanoparticles arecoated with at least one lipid lamella consisting of at least onesurfactant capable of forming vesicles, the compositions according tothe invention can exhibit especially advantageous cosmetic features.These coated nanoparticles can constitute only a part of thenanoparticles of the composition.

[0029] The examples given below, purely by way of illustration andwithout implied limitation, will facilitate understanding of theinvention.

EXAMPLE 1

[0030] In this example, for the purpose of comparison, an aqeuousdispersion of nanoparticles of polymer of butyl cyanoacrylate containingα-tocopherol, prepared according to the procedure of Example 3, in anaqueous phase containing a surfactant and ethanol, and two emulsions ofα-tocopherol in water obtained using two different emulsifiers, werestudied. Skin irritation (SIR) and eye irritation (EI) were thenmeasured.

[0031] The SIR measurements were performed according to the protocoldescribed in the Ministerial Decree of Feb. 1, 1982, published in theJournal Officiel de la République Française (J.O.R.F) (Official Journalof the French Republic) dated Feb. 21, 1982.

[0032] The EI measurements were-performed according to the protocoldescribed in the Ministerial Decree of Sep. 21, 1984, published in theJ.O.R.F. of Oct. 24, 1984 and Feb. 9, 1985.

[0033] The compositions and results are given in Table I. TABLE IEmulsion No. 1 Emulsion No. 2 Nanoparticles not according not accordingComposition according to to the to the in % the invention inventioninvention α-Tocopherol 1.0 1.0 1.0 Butyl cyano- 0.2 — — acrylateSolubilisant S 12 — 2.0 — Solulan 16 — — 2.0 Pluronic F 68 0.2 — —Kathon CG 0.1 0.1 0.1 Water qs 100 qs 100 qs 100 Nature of themeasurement Results SIR 0.08 0.29 2.0 EI 2.6 at 1H 11.83 at 1H  5.67 at1H ″ 1.0 at 1D 1.67 at 1D 2.33 at 1D ″ 0.0 at 2D 0.67 at 2D 1.33 at 2D ″ 0.0 at 3D  0.0 at 3D

[0034] In this Table I:

[0035] H denotes hour and D denotes day.

[0036] “Solubilisant S 12” is an emulsifier consisting of anoxyethylenated nonylphenol containing 12 moles of ethylene oxide, soldby the company “GIVAUDAN”.

[0037] “Solulan 16” is an emulsifier consisting of a mixture (lanolinalcohols/oxyethylenated fatty alcohols containing 16 moles of ethyleneoxide) sold by the company “AMERCHOL”.

[0038] “Pluronic F 68” is a surfactant consisting of a condensate ofethylene oxide and propylene oxide, sold by the company “BASF”.

[0039] “Kathon CG” is a preservative consisting of a mixture of5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-oneand magnesium chloride and nitrate, sold by the company “ROHM and HAAS”.

[0040] According to this table, it is seen that, to obtain the emulsions1 and 2, 2% of emulsifier was needed in order to microdisperse 1% ofα-tocopherol. On the other hand, it is seen that the composition basedon nanoparticles proves distinctly less irritant to the skin than thetwo emulsions, and that eye irritation (EI) is also reduced, both afterone hour and after two days.

EXAMPLE 2

[0041] In this further comparative example, an aqueous dispersion ofnanoparticles according to the invention, having the following weightcomposition, was prepared according to the procedure of Example 4:

[0042] α-Tocopherol . . . 5%

[0043] Butyl cyanoacrylate . . . 1%

[0044] Surfactant sold by the company “ICI” under the trade name“SYMPERONIC PE/F68” . . . 1%

[0045] Preservative sold by the company “ROHM and HAAS” under the tradename “KATHON CG” . . . 0.1%

[0046] Water . . . 92.9%

[0047] A placebo having the following composition was also prepared:

[0048] Oil sold by the company “DYNAMIT NOBEL” under the trade name“MIGLYOL 812” . . . 5%

[0049] Butyl cyanoacrylate . . . 1%

[0050] Surfactant sold by the company “ICI” under the trade name“SYMPERONIC PE/F68” 1%

[0051] Preservative sold by the company “ROHM and HAAS” under the tradename “KATHON CG” . . . 0.1%

[0052] Water . . . 92.9%

[0053] The free radical-inhibiting effect of the aqueous dispersion ofnanoparticles and of the placebo was then assessed in vivo in hairlessmice by subjecting them to UV radiation and measuring the content ofmalonodialdehyde (MDA) in the skin, since MDA formation is induced by UVradiation.

[0054] The mice are treated with a given number of applications of thetest product. Each application is performed on the back of the mousewith 13.5 mg of preparation uniformly distributed over 4.5 cm², and,when there are several applications, at 24-hour intervals.

[0055] One hour after the final application, the mice are subjected toUV radiation using an apparatus of the “BIOTRONIC UV 365/312 nm” type,which emits a spectrum with absorption peaks at 365 nm (for UV-A)provided by 2 40-W tubes and at 312 nm (for UV-B) provided by a 40-Wtube. The irradiations are performed at doses of 4.00 J/cm² in UV-A and4.00 J/cm² in UV-B. Three hours after completion of the irradiation, themice are sacrificed and the irradiated skin is cut out. After severalwashes, the application surface is wiped and a 100 mg fragment isintroduced into 1.8 ml of phosphate buffer and then ground in an“ULTRA-TURRAX” for 1 min. The MDA is then assayed in a trichloroaceticacid medium and in the heated state by adding thiobarbituric acid, whichcombines with MDA to form a pink complex, and by measuring theconcentration of this coloured complex in a spectrophotometer.

[0056] The results are given in Table II: TABLE II MDA content (MEAN +SEM) in Number of applications nanomoles MDA/mg Test before irradiationprotein Unirradiated 0 2.655 ± 0.048 control Irradiated 0 3.780 ± 0.277control Nanoparticles 1 2.651 ± 0.199 ″ 4 2.461 ± 0.255 Placebo 1 4.190± 0.323 ″ 4 3.800 ± 0.326

[0057] It is seen in this table that the effect of the active ingredientencapsulated in the nanoparticles is maximal from the first applicationonwards, and hence immediate.

EXAMPLE 3

[0058] In this third comparative example, a dispersion of nanoparticlesaccording to the invention, having the following weight composition, wasprepared according to the procedure of Example 4:

[0059] Surfactant sold by the company “BASF” under the trade name“PLURONIC F 68” . . . 0.6%

[0060] Preservative sold by the company “ROHM & HAAS” under the tradename “KATHON CG” . . . 0.05%

[0061] Butyl cyanoacrylate . . . 0.3%

[0062] α-Tocopherol, radiolabelled . . . 1.5%

[0063] Water q.s. . . . 100%

[0064] The radioactivity concentration of the dispersion is 120 μCi/ml.

[0065] Furthermore, a solution (not according to the invention)containing 1.5% by weight of radiolabelled α-tocopherol in silicone oilsold by the company “DOW CORNING” under the trade name “DC 200 FLUID”was prepared. The radioactivity concentration of the solution is 72μCi/ml.

[0066] The penetration of the α-tocopherol in the dispersion ofnanoparticles and in the solution in silicone oil into the differentlayers of the skin was then assessed. The study was performed in vitrowith Franz cells, cells described in “The Journal of InvestigativeDermatology, volume 64 (1975), pages 190-195”.

[0067] Skin biopsies were prepared from hairless female rats weighing230-250 g. Identical amounts of labelled α-tocopherol, in encapsulatedform in nanoparticles on the one hand, and in the form of a solution insilicone oil on the other hand, were applied to the surface of thesebiopsies on the stratum corneum side; they were left in contact for 24hours. The dermis was then separated mechanically from the epidermis,and the α-tocopherol:

[0068] which had passed through the skin A

[0069] found in the skin

[0070] in the epidermis B

[0071] and in the dermis C

[0072] which had not penetrated into the skin D was assayed.

[0073] The results obtained are collated in Table III below, where theyare given in percentages by weight of α-tocopherol for 100% ofα-tocopherol applied. TABLE III α-tocopherol (% by weight) Test A B C DSilicone oil 0.73 25.6 24.3 54.4 Nanoparticles 0.42 63.8 17.9 16.7

[0074] In this table, it may be observed that the amount of α-tocopherolwhich has passed through the skin is significantly higher in the case ofthe solution in silicone oil than in the case of the dispersion ofnanoparticles, but remains very small in both cases. Moreover, the totalamount of α-tocopherol retained in the skin (epidermis and dermis) ismuch higher in the case of the dispersion of nanoparticles than in thecase of the solution in silicone oil, the majority of the α-tocopherolremaining in the epidermis in the case of the dispersion ofnanoparticles.

EXAMPLE 4

[0075] In a 1250-ml beaker, 1 g of a mixture of condensates of ethyleneoxide and propylene oxide (20%/80% by weight), of average molecularweights 1750 and 8350, respectively, sold by the company “BASF” underthe trade name “PLURONIC F-68), is dissolved in 500 ml of demineralizedwater with stirring provided by a bar magnet rotating at 400 rpm.

[0076] 620 ml of absolute ethanol in which the following have beendissolved beforehand:

[0077] 5 g of α-tocopherol, and

[0078] 1 g of n-butyl cyanoacrylate are poured slowly dropwise into thisaqueous phase.

[0079] Stirring is maintained for two hours while the temperature of thereaction medium is adjusted to 20° C. using a thermostated bath. Afterthese two hours, the dispersion of nanoparticles obtained is transferredto a 1-liter round-bottomed flask which is placed on a rotaryevaporator, and the ethanol and a part of the water are evaporated off.

[0080] 95 g of a colloidal dispersion of nanoparticles are recoveredcontaining 5 g of encapsulated α-tocopherol, the diameter and the indexof polydispersity (IP) of which, measured in a “nanosizer” (Coultronicsparticle size analyser), are 190 nm and 1, respectively.

[0081] The index IP is assessed on a scale from 0 to 9, 0 correspondingto a very homogeneous size dispersion whereas an index of 9 indicates ahigh ratio of the size of the largest particles to that of the smallest.

[0082] 5 g of an aqueous solution containing 0.1 g of a preservativesold by the company “ROHM & HAAS” under the trade name “KATHON CG” arefinally added.

EXAMPLE 5

[0083] An aqueous dispersion having the following composition wasprepared according to the same procedure as in Example 4:

[0084] Condensates of ethylene oxide and propylene oxide, sold by thecompany “BASF” under the trade name “PLURONIC F-68” . . . 0.4 g

[0085] Safflower oil . . . 1.0 g

[0086] Isohexyl cyanoacrylate . . . 0.4 g

[0087] Water q.s. . . . 100 g

[0088] Nanoparticles having an average diameter of 250 nm, with an indexIP equal to 2, are obtained.

EXAMPLE 6

[0089] An aqueous dispersion having the following composition wasprepared according to the same procedure as in Example 4:

[0090] Condensates of ethylene oxide and propylene oxide, sold by thecompany “BASF” under the trade name “PLURONIC F-68” . . . 0.2 g

[0091] Pentaerythritol tetra(2-ethylhexanoate) 1.0 g

[0092] Butyl cyanoacrylate . . . 0.2 g

[0093] Water q.s. . . . 100 g

[0094] Nanoparticles having an average diameter of 250 nm, with an indexIP equal to 1, are obtained.

EXAMPLE 7

[0095] An aqueous dispersion having the following composition wasprepared according to the same procedure as in Example 4:

[0096] Condensates of ethylene oxide and propylene oxide, sold by thecompany “BASF” under the trade name “PLURONIC F-68” . . . 0.4 g

[0097] Triglycerides sold by the company “DYNAMIT NOBEL” under the tradename “MIGLYOL 812” 1.0 g

[0098] Vitamin A palmitate . . . 0.02 g

[0099] Butyl cyanoacrylate . . . 0.2 g

[0100] Water q.s. . . . 100 g

[0101] Nanoparticles having an average diameter of 240 nm, with an indexIP equal to 2, are obtained.

EXAMPLE 8

[0102] In a 200-ml beaker, 0.3 g of crosslinked polyacrylic acid, soldby the company “GOODRICH” under the trade name “CARBOPOL 940”, isswollen in 41.1 g of water containing 0.1 g of methylpara-hydroxybenzoate dissolved beforehand. This operation is carried outat a temperature of 80° C.; the mixture is then gradually brought downto a temperature of 40° C. 5 g of water containing 0.1 g of natural gumsold by the company “SATIA” under the trade name “AUBY GUM X2” areadded.

[0103] After homogenisation, the mixture is brought down to roomtemperature and 10 g of aqueous solution obtained by grinding animalplacental tissues, sold by the company “GATTEFOSSE” finder the tradename “PHYLDERM”, and

[0104] 2 g of glycerol,

[0105] 1 g of hexylene glycol,

[0106] 15 g of rose water are added.

[0107] After homogenisation, 0.1 g of the preservative sold by thecompany “DOW CHEMICAL” under the trade name “DOWICIL 200”, dissolvedbeforehand in 5 g of water, is added. 10 g of the aqueous dispersion ofnanoparticles prepared in Example 4 and 10 g of the aqueous dispersionof nanoparticles prepared according to Example 7 are added. Afterhomogenisation, 0.3 g of triethanolamine is added. A bluish-whitephysiological fluid having a viscosity equal to 1.6 poises and a pHequal to 7 is thereby obtained.

[0108] This physiological fluid is applied once a day to the cleansedskin of the face. After fifteen days' application, an effect ofsmoothing the skin of the face is observed.

EXAMPLE 9

[0109] In a 200-ml beaker, the following are dissolved in 25 g of rosewater:

[0110] 0.25 mg of dye “FD and C BLUE 1” marketed by the company “ALLIEDCHEMICAL”; and

[0111] 0.1 g of dye “D and C YELLOW 10” marketed by the company“ANSTEAD”.

[0112] 30.2 g of water containing 0.9 g of sodium chloride are thenadded, followed by 1.0 g of butylene glycol and 2.0 g of glycerol.

[0113] The mixture is homogenised and there are then added 20 g of waterin which 0.05 g of crosslinked polyacrylic acid sold by the company“GOODRICH” under the trade name “CARBOPOL 1342” has been swollen.

[0114] After homogenisation, 20 g of the aqueous dispersion ofnanoparticles obtained in Example 6 are then added. 0.05 g oftriethanolamine dissolved in 0.83 g of water is finally added. A green,very fluid moisturising lotion having a pH equal to 6.7 is therebyobtained.

[0115] This lotion is applied twice a day after cleansing the face,especially by individuals with dry skin. After one month's application,it is observed that the skin of the face is more supple, and that thesensation of tightness caused by the dryness of the skin is attenuated.

EXAMPLE 10

[0116] 380.50 g of floral water in which the following are dissolved:

[0117] 0.5 g of hamamelis essence in a glycol carrier, marketed by thecompany “SOSHIBO”,

[0118] 2.5 g of hexylene glycol,

[0119] 10.0 g of glycerol, and

[0120] 1.0 g of condensates of ethylene oxide and propylene oxide, soldby the company “BASF” under the trade name “PLURONIC F-68” are pouredinto the 1-liter glass vessel of a “COS 1000” homogeniser marketed bythe company “COSMETOCHEM”.

[0121] This solution is homogenised by means of a scraper rotating at aspeed of 30 rpm and an impeller rotating at 90 rpm, the preparationvessel being thermostated at a temperature of 20° C. During thishomogenisation, an alcoholic solution composed of:

[0122] ethanol . . . 75 g

[0123] butyl cyanoacrylate . . . 0.5 g

[0124] α-tocopherol acetate . . . 5.0 g is added in continuous fashionin the course of 20 minutes.

[0125] After complete introduction of the alcohol phase, the speed ofthe impeller is reduced to 70 rpm and this stirring is maintained fortwo hours.

[0126] 24.25 g of water containing the following preservatives in thedissolved state are then added:

[0127] Preservative sold by the company “DOW CHEMICAL” under the tradename “DOWICIL 200” . . . 0.5 g

[0128] Preservative sold by the company “ROHM & HAAS” under the tradename “KATHON CG” . . . 0.25 g

[0129] 500 g of an alcoholic lotion are thereby obtained. The averagediameter of the nanoparticles obtained is measured using a “BI 90”particle size analyser (sold by the company “BROOKHAVEN”): it is 225 nm;the index of polydispersity is 2.

[0130] This lotion is applied to the body every day after a shower orbath, especially during periods of frequent exposure to sunlight. Itexerts a protective action on the skin against the harmful effects ofsolar radiation.

EXAMPLE 11

[0131] In a 200-ml glass beaker, the following are dissolved in 24 g ofliquid paraffin heated to a temperature of 65° C.:

[0132] 5 g of cetyl alcohol, and

[0133] 3 g of a polyethylene glycol monostearate containing 50 moles ofethylene oxide, sold by the company “ICI” under the trade name “MYRJ53”.

[0134] After the mixture has been brought down to a temperature of 50°C., an aqueous phase at the same temperature consisting of:

[0135] a solution in 44.7 g of water of 0.3 g of the mixture ofpreservatives sold by the company “LSN” under the trade name “ELESTAB4112”, and

[0136] 20 g of the aqueous dispersion of nanoparticles obtained inExample 4 is added with stirring provided by a “MORITZ” homogeniser.

[0137] Homogenisation is maintained during cooling of the product toroom temperature. 100 g of a thick white cream which has a protectiveeffect against solar radiation are thereby obtained.

[0138] This cream is applied daily to a perfectly cleansed skin; it isintended, more especially, for skins exposed daily to solar radiation.

EXAMPLE 12

[0139] In a 200-ml glass beaker, the following compounds are mixed at atemperature of 85° C. using a “MORITZ” homogeniser:

[0140] Product sold by the company “CHIMEX” under the trade name“MEXANYL GO” . . . 5.70 g

[0141] Hydrogenated lanolin sold by the company “RITA” under the tradename “SUPERSAT” . . . 6.65 g

[0142] Product manufactured by the company “CHIMEX”, sold under thetrade name “MEXANYL GP” . . . 2.00 g

[0143] After homogenisation, this first mixture is dissolved in a secondmixture consisting of:

[0144] Liquid purcellin oil . . . 3.00 g

[0145] Product sold by the company “CRODA” under the trade name “Liquidbase CB 1145” . . . 3.00 g

[0146] Isopropyl palmitate . . . 4.75 g

[0147] Liquid paraffin . . . 7.9 g

[0148] White vaseline . . . 15 g

[0149] Perhydrosqualene . . . 0.4 g

[0150] These two mixtures are homogenised at a temperature of 80° C. andthen cooled to a temperature of 40° C. 0.8 g of perfume sold by thecompany “FIRMENICH” under the trade name “CHEMODERM 1008” is then added.

[0151] An aqueous phase consisting of a mixture of a solution of 0.25 gof the mixture of preservatives sold by the company “LSN” under thetrade name “ELESTAB 4110”, in 29.9 g of water, and 20 g of the aqueousdispersion of nano particles obtained in Example 5 is then introducedwith stirring and at a temperature of 40° C.

[0152] This stirring is maintained for 20 minutes, and 0.3 g ofpreservative sold by the company “ROHM & HAAS” under the trade name“GERMAL 115”, treated with 0.35 g of water, is then added.

[0153] After return of the mixture to room temperature, the productobtained is transferred to a triple-roller type mill.

[0154] A thick, smooth white cream is thereby obtained, intended for thecare of very dry and aged skins. After a twice-daily application of thiscream for 15 days, an improvement of the surface condition of thetreated skin is observed.

EXAMPLE 13

[0155] An aqueous dispersion having the following composition isprepared according to the same procedure as in Example 4:

[0156] Condensate of ethylene oxide and propylene oxide, sold by thecompany “BASF” under the trade name “Pluronic F 68” . . . 0.25 g

[0157] Bisabolol . . . 0.5 g

[0158] α-Tocopherol acetate . . . 0.5 g

[0159] Butyl cyanoacrylate . . . 0.2 g

[0160] Water q.s. . . . 100 g

[0161] Nanoparticles having an average diameter of 215 nm, with an indexIP equal to 1, are obtained.

EXAMPLE 14

[0162] An aqueous dispersion having the following composition wasprepared according to the same procedure as in Example 4:

[0163] Condensate of ethylene oxide and propylene oxide, sold by thecompany “BASF” under the trade name “Pluronic F 68” . . . 0.25 g

[0164] Mixture of decyl oleate, farnesol, ethyl linoleate and farnesylacetate, sold by the company “Induchem” under the trade name “UnibiovitB 33” . . . 1.0 g

[0165] Butyl cyanoacrylate . . . 0.2 g

[0166] Water q.s. . . . 100 g

[0167] Nanocapsules having an average diameter of 240 nm, with an indexIP equal to 2, are obtained.

EXAMPLE 15

[0168]1) Preparation of the dispersion of vesicles:

[0169] 0.05 g of dimyristyl phosphate and 0.95 g of nonionic surfactantof formula (I):

[0170] in which:

[0171] —OC₂H₃ (R′)— denotes the following structures, taken mixed orseparately:

[0172] —C₃H₅(OH)O— denotes the following structures, taken mixed orseparately:

[0173] n is an average statistical value equal to 6;

[0174] R═C₁₂H₂₅ and R′ represents an equimolar mixture of tetradecyl andhexadecyl radicals, are weighed into a 100-ml glass beaker.

[0175] These two lipids are homogenised by heating on a hotplate to atemperature of 100° C., and the mixture is then cooled to 40° C. 27.6 gof water in which 3 g of glycerol and 0.02 g of citric acid have beendissolved beforehand are then added. The whole is homogenised by theaction of a “Virtis” type ultradisperser for 2 minutes at a speed of40,000 rpm at a temperature of 40° C. There are then added 3 g of waterin which 0.1 g of preservative sold by the company “Rohm and Haas” underthe trade name “Kathon CG” and 0.2 g of preservative sold by the company“Rohm and Haas” under the trade name “Germal 115” have been dissolvedbeforehand.

[0176] The fatty phase composed of the following mixture of products isthen added:

[0177] macadamia oil . . . 9 g

[0178] volatile silicone oil . . . 7 g

[0179] ethylhexyl para-methoxycinnamate sold by the company “Givaudan”under the trade name “Parsol MCX” . . . 0.5 g

[0180] 2-hydroxy-4-methoxybenzophenone sold by the company “BASF” underthe trade name “Uvinul M40” . . . 0.5 g

[0181] propyl para-hydroxybenzoate . . . 0.05 g

[0182] The whole is subjected to the action of a “Virtis” ultradisperserfor 5 minutes at room temperature.

[0183] 2) Mixing of the dispersions of vesicles and nanoparticles.

[0184] 20 g of the aqueous dispersion of nanoparticles obtained inExample 4 are then added. 35 g of water in which 0.65 g ofvinylcarboxylic acid sold by the company “Goodrich” under the trade name“Carbopol 940” has been swollen are then added. After homogenisation,0.65 g of triethanolamine diluted with 1.73 g of water is finally added.A thick white cream of shiny appearance, intended for care of the face,is thereby obtained. After an application of this cream once a day for15 days, an improvement in the surface condition of the treated skin isobserved.

EXAMPLE 16

[0185] In a 100-ml beaker, 250 mg of condensate of ethylene oxide andpropylene oxide (20/80%), of average molecular weights 1750 and 8350,respectively, sold by the company “BASF” under the trade name “PluronicF68”, are dissolved in 50 ml of demineralised water with stirringprovided by a bar magnet rotating at 400 rpm. Into this aqueous phasethermostated at a temperature of 40° C., 25 ml of acetone in which thefollowing have been dissolved beforehand at a temperature of 40° C.:

[0186] 125 mg of DL-polylactic acid sold by the company “Polysciences”

[0187] 500 mg of α-tocopherol acetate sold by the company “Roche”, and

[0188] 2 mg of “Nile Red” dye (Nile Blue A Oxazone) sold by the company“Sigma”, are poured slowly.

[0189] Stirring is maintained for 2 hours at a temperature of 40° C. andthe mixture is then brought down to room temperature. The dispersion ofnanoparticles obtained is then transferred to a 250-ml round-bottomedflask which is placed on a rotary evaporator, and the acetone isevaporated off. A fluid colloidal dispersion of nanoparticles having anaverage diameter of 295 nm, with an index IP equal to 2, is therebyobtained.

[0190] On microscopic examination under fluorescence conditions, a densepopulation of nanoparticles fluorescent to the core, with a clearlydistinctive identity, homogeneous in size and agitated in Brownianmovement, is observed. After 2 months' storage at temperatures of +4,25, 37 and 45° C., no modification of the appearance of thenanoparticles is observed on examination under fluorescence conditions,nor are large variations observed in their size (in all cases, thevariations are less than 10% of the initial average diameter).

EXAMPLE 17

[0191] In a 100-ml beaker, 250 mg of condensate of ethylene oxide andpropylene oxide (20/80%), of average molecular weights 1750 and 8350,respectively, sold by the company “BASF” under the trade name “PluronicF68”, are dissolved in 50 ml of demineralised water with stirringprovided by a bar magnet rotating at 400 rpm. Into this aqueous phasethermostated at a temperature of 40° C., 25 ml of acetone in which 125mg of soybean lecithin, sold by the company “Lucas Meyer” under thetrade name “Epikuron 170” have been dissolved beforehand at atemperature of 55° C. are poured slowly; then, after the mixture hasbeen brought down to a temperature of 40° C., the following aredissolved:

[0192] 125 mg of DL-polylactic acid sold by the company “Polysciences”,

[0193] 500 mg of α-tocopherol acetate sold by the company “Roche”, and

[0194] 2 mg of “Nile Red” dye (Nile Blue A Oxazone) sold by the company“Sigma”.

[0195] Stirring is maintained for 2 hours at a temperature of 40° C. andthe mixture is there brought down to room temperature. The dispersion ofnanoparticles obtained is then transferred to a 250-ml round-bottomedflask which is placed on a rotary evaporator, and the acetone isevaporated off. A fluid white colloidal dispersion of nanoparticleshaving an average diameter of 225 nm, with an index IP equal to 2, isthereby obtained.

[0196] On microscopic examination under fluorescence conditions, a densepopulation of nanoparticles fluorescent to the core, with a clearlydistinctive identity, homogeneous in size and agitated in Brownianmovement, is observed. After 2 months' storage at temperatures of +4,25, 37 and 45° C., no modification of the appearance of thenanoparticles is observed on examination by fluorescence microscopy, norare large variations observed in their size (in all cases, thevariations are less than 10% of the initial average diameter).

EXAMPLE 18

[0197] In a 100-ml beaker, 250 mg of condensate of ethylene oxide andpropylene oxide (20/80%), of average molecular weights 1750 and 8350,respectively, sold by the company “BASF” under the trade name “PluronicF68”, are dissolved in 50 ml of demineralised water with stirringprovided by a bar magnet rotating at 400 rpm. Into this aqueous phasethermostated at a temperature of 40° C., 25 ml of acetone in which thefollowing have been dissolved beforehand at a temperature of 40° C.

[0198] 125 mg of DL-polylactic acid sold by the company “Polysciences”,and

[0199] 500 mg of α-tocopherol acetate sold by the company “Roche” arepoured slowly.

[0200] Stirring is maintained for 2 hours at a temperature of 40° C. andthe mixture is then brought down to room temperature. The dispersion ofnanoparticles obtained is then transferred to a 250-ml round-bottomedflask which is placed on a rotary evaporator, and the acetone isevaporated off. A fluid white colloidal dispersion of nanoparticleshaving an average diameter of 310 nm, with an index IP equal to 2, isthereby obtained.

[0201] On microscopic examination, a dense population of nanoparticleswith a clearly distinctive identity, homogeneous in size and agitated inBrownian movement, is observed. After 2 months' storage at temperaturesof +4, 25, 37 and 45° C., no modification of the appearance of thenanocapsules is observed, nor are large variations observed in theirsize (in all cases, the variations are less than 10% of the initialaverage diameter).

EXAMPLE 19

[0202] In a 100-ml beaker, 250 mg of condensate of ethylene oxide andpropylene oxide (20/80%), of average molecular weights 1750 and 8350,respectively, sold by the company “BASF” under the trade name “PluronicF68”, are dissolved in 50 ml of demineralised water with stirringprovided by a bar magnet rotating at 400 rpm. Into this aqueous phasethermostated at a temperature of 40° C., 25 ml of acetone in which 250mg of soybean lecithin, sold by the company “Lucas Meyer” under thetrade name “Epikuron 170”, have been dissolved beforehand at atemperature of 55° C. are poured slowly; then, after the mixture hasbeen brought down to a temperature of 40° C., the following aredissolved:

[0203] 125 mg of DL-polylactic acid sold by the company “Polysciences”,and

[0204] 500 mg of ethylhexyl para-methoxycinnamate marketed by thecompany “Givaudan” under the trade name “Parsol MCX”.

[0205] Stirring is maintained for 2 hours at a temperature of 40° C. andthe mixture is then brought down to room temperature. The dispersion ofnanoparticles obtained is then transferred to a 250-ml round-bottomedflask which is placed on a rotary evaporator, and the acetone isevaporated off. A fluid white colloidal dispersion of nanoparticleshaving an average diameter of 240 nm, with an index IP equal to 2, isthereby obtained.

[0206] On microscopic examination in white light, a dense population ofnanoparticles with a clearly distinctive identity, homogeneous in sizeand agitated in Brownian movement, is observed. After 2 months' storageat temperatures of +4, 25, 37 and 45° C., no modification of theappearance of the nanoparticles is observed on microscopic examination,nor are large variations observed in their size (in all cases, thevariations are less than 10% of the initial average diameter).

EXAMPLE 20

[0207] In a 100-ml beaker, 250 mg of condensate of ethylene oxide andpropylene oxide (20/80%), of average molecular weights 1750 and 8350,respectively, sold by the company “BASF” under the trade name “PluronicF68”, are dissolved in 50 ml of demineralised water with stirringprovided by a bar magnet rotating at 400 rpm. Into this aqueous phase,25 ml of acetone, in which 500 mg of α-tocopherol acetate and 125 mg ofpolymer of butyl cyanoacrylate obtained by prior self-polymerisation inwater of butyl cyanoacrylate monomer, isolation by centrifugation andthen drying by lyophilisation has been dissolved beforehand, are pouredslowly. Stirring is maintained for 2 hours at room temperature. Thedispersion of nanoparticles obtained is then transferred to a 250-mlround-bottomed flask which is placed on a rotary evaporator, and theacetone is evaporated off. A fluid colloidal dispersion of nanoparticleshaving an average diameter of 220 nm, with an index IP equal to 1, isthereby obtained.

[0208] On microscopic examination under fluorescence conditions, a densepopulation of nanoparticles fluorescent to the core, with a clearlydistinctive identity, homogeneous in size and agitated in Brownianmovement, is observed. After 2 months' storage at temperatures of +4,25, 37 and 45° C., no modification of the appearance of thenanoparticles is observed on examination under fluorescence conditions,nor are large variations observed in their size (in all cases, thevariations are less than 10% of the initial average diameter).

EXAMPLE 21

[0209] In a 100-ml beaker, 250 mg of condensate of ethylene oxide andpropylene oxide (20/80%), of average molecular weights 1750 and 8350,respectively, sold by the company “BASF” under the trade name “PluronicF68”, are dissolved in 50 ml of demineralised water with stirringprovided by a bar magnet rotating at 400 rpm. Into this aqueous phasethermostated at a temperature of 40° C., 25 ml of acetone in which 250mg of soybean lecithin, sold by the company “Lucas Meyer” under thetrade name “Epikuron 170”, have been dissolved beforehand at atemperature of 55° C. are poured slowly; then, after the mixture hasbeen brought down to a temperature of 40° C., the following aredissolved:

[0210] 500 mg of α-tocopherol acetate marketed by the company “Roche”,and

[0211] 125 mg of copoly(DL-lactide/glycolide) (in the mole ratio 50:50)marketed by the company “Dupont de Nemours” under the trade name“Medisorb T. M.”.

[0212] Stirring is maintained for 2 hours at a temperature of 40° C. andthe mixture is then brought down to room temperature. The dispersion ofnanoparticles obtained is then transferred to a 250-ml round-bottomedflask which is placed on a rotary evaporator, and the acetone isevaporated off. A fluid colloidal dispersion of nanoparticles having anaverage diameter of 210 nm, with an index IP equal to 1, is therebyobtained.

[0213] On microscopic examination under fluorescence conditions, a densepopulation of nanoparticles fluorescent to the core, with a clearlydistinctive identity, homogeneous in size and agitated in Brownianmovement, is observed. After 2 months' storage at temperatures of +4,25, 37 and 45° C., no modification of the appearance of thenanoparticles is observed on examination under fluorescence conditions,nor are large variations obsreved in their size (in all cases, thevariations are less than 10% of the initial average diameter).

EXAMPLE 22

[0214] In a 100 ml beaker, 250 mg of condensate of ethylene oxide andpropylene oxide (20/80%), of average molecular weights 1750 and 8350,respectively, sold by the company “BASF” under the trade name “PluronicF68”, are dissolved in 50 ml of demineralised water with stirringprovided by a bar magnet rotating at 400 rpm. Into this aqueous phasethermostated at a temperature of 40° C., 25 ml of acetone in which 250mg of soybean lecithin, sold by the company “Lucas Meyer” under thetrade name “Epikuron 170”, have been dissolved beforehand at atemperature of 55° C. are poured slowly; then, after the mixture hasbeen brought down to a temperature of 40° C., the following aredissolved:

[0215] 500 mg of α-tocopherol acetate marketed by the company “Roche”,and

[0216] 125 mg of polycaprolactone marketed by the company “Aldrich”.

[0217] Stirring is maintained for 2 hours at a temperature of 40° C. andthe the mixture is then brought down to room temperature. The dispersionof nanoparticles obtained is then transferred to a 250-ml round-bottomedflask which is placed on a rotary evaporator, and the acetone isevaporated off. A fluid colloidal dispersion of nanoparticles having anaverage diameter of 195 nm, with an index IP equal to 2, is therebyobtained.

[0218] On microscopic examination in white light, a dense population ofnanoparticles with a clearly distinctive identity, homogeneous in sizeand agitated in Brownian movement, is observed. After 2 months' storageat temperatures of +4, 25, 37 and 45° C., no modification of theappearance of the nanoparticles is observed on examination underfluorescence conditions, nor are large variations observed in their size(in all cases, the variations are less than 10% of the initial averagediameter).

EXAMPLE 23

[0219] The following are weighed into a 200-ml fluted glass vessel:

[0220] 2.5 g of an aqueous-alcoholic gel consisting of soybean lecithin(20%), absolute ethanol (16 degrees alcohol strength) and water,marketed by the company “Natterman” under the trade name “Natipide II”,

[0221] 0.01 g of ascorbyl palmitate,

[0222] 5.0 g of glycerol, and

[0223] 17.5 g of water.

[0224] The whole is homogenised at room temperature using a “Virtis”ultradisperser for 3 minutes at a speed of 30,000 rpm. A dispersion ofliposomes having an average size of 200 nm is thereby obtained.

[0225] 1 g of polyethylene glycol 400 and 3.0 g of propylene glycol arethen added: the whole is mixed at room temperature for 1 minute with the“Virtis” ultradisperser. 10 g of aqueous solution obtained by grindinganimal placental tissues, sold by the company “Gattefossé” under thetrade name “Phylderm”, are added: the whole is mixed at room temperaturefor 1 minute with the “Virtis” ultradisperser. 0.2 g of methylpara-hydroxybenzoate, dissolved in 30.19 g of water beforehand, isadded: the whole is mixed at room temperature for 1 minute with the“Virtis” ultradisperser. 0.1 g of sodium hyaluronate swollen beforehandin 10 g of water, marketed by the company “Biotechnology”, is added.

[0226] 0.25 g of the mixture of vinylcarboxylic acids sold by thecompany “Goodrich” under the trade name “Carbopol 940”, swollenbeforehand in 10 g of water, is then added. The whole is mixed at roomtemperature for 3 minutes with the “Virtis” ultradisperser at a speed of20,000 rpm. 0.25 g of triethanolamine is added and the mixture ishomogenised for 30 seconds with the “Virtis” ultradisperser. Finally, 10g of dispersion of nanoparticles prepared in Example 3 are added. Thewhole is homogenised using a “Heidolph” paddle homogeniser at a speed of800 rpm for 30 minutes.

[0227] A beige physiological fluid is thereby obtained, which will beapplied once a day to the cleansed skin of the face, before and afterperiods of exposure to sunlight. It is found that, despite the highfrequency of exposure to sunlight and the duration of such periods ofexposure, the skin shows no trace of irritation.

1. Composition for the cosmetic and/or pharmaceutical treatment of theupper layers of the epidermis, by topical application to the skin,characterised in that it comprises, in a suitable vehicle, biodegradablepolymer nanoparticles encapsulating at least one active ingredient inthe form of an oil and/or at least one active ingredient contained in aninactive carrier oil or an active oil, the active ingredient beingselected from those having a cosmetic and/or pharmaceutical action. 2.Composition according to claim 1 , characterised in that thenanoparticles are between 10 and 1,000 nm in size.
 3. Compositionaccording to one of claims 1 and 2, characterised in that the weight ofthe nanoparticles loaded with at least one active ingredient constitutesfrom 0.1% to 20% of the total weight of the composition.
 4. Compositionaccording to one of claims 1 to 3 , characterised in that the polymerconstituting the nanoparticles is selected from the group composed ofpolymers of (C₂-C₁₂) alkyl cyanoacrylate, poly-L-lactides,poly-DL-lactides, polyglycolides, polycaprolactones, polymers of3-hydroxybutyric acid, copoly(DL-lactides/glycolides) andcopoly(glycolides/caprolactones).
 5. Composition according to claim 4 ,characterised in that the polymer constituting the nanoparticles is a(C₂-C₆) alkyl cyanoacrylate.
 6. Composition according to claim 5 ,characterised in that the alkyl radical of the cyanoacrylate is selectedfrom the group composed of ethyl, n-butyl, hexyl, isobutyl and isohexylradicals.
 7. Composition according to one of claims 1 to 6 ,characterised in that the active ingredient in the form of an oil or theactive oil is selected from the group composed of α-tocopherol,α-tocopherol acetate, triglycerides rich in linoleic and/or linolenicacid(s), pentaerythritol tetra(2-ethylhexanoate), clofibrate, tocopherollinoleate, fish oil, hazelnut oil, bisabolol, farnesol, farnesylacetate, ethyl linoleate and ethylhexyl para-methoxycinnamate. 8.Composition according to one of claims 1 to 7 , characterised in thatthe inactive carrier oil is selected from the group composed oftriglycerides, simple or modified by oxyethylenation, volatile siliconeoils and mixtures thereof.
 9. Composition according to one of claims 1to 8 , characterised in that the active ingredient contained in an oilis selected from the group composed of emollients, humectants, freeradical-inhibiting agents, anti-inflammatories, vitamins, depigmentingagents, anti-acne agents, antiseborrhoeics, keratolytics, slimmingagents and skin colouring agents.
 10. Composition according to one ofclaims 1 to 9 , characterised in that the weight ratio of thebiodegradable polymer of the nanoparticles to the active oily phase isbetween 0.05 and 0.5.
 11. Composition according to one of claims 1 to 10, characterised in that it takes the form of a physiological fluid, alotion, an aqueous, aqueous alcoholic or oily gel or a water-in-oil oroil-in-water emulsion, or alternatively of aqueous dispersions ofvesicles in which the constituent lipids are ionic or nonionic lipids ora mixture of ionic and nonionic lipids, with or without an oily phase.12. Composition according to one of claims 1 to 10 , characterised inthat at least a part of its nanoparticles contains at least one lipidlamella around the polymer membrane of the nanoparticle.
 13. Process forpreparing a composition according to one of claims 1 to 12 ,characterised in that, to obtain the nanoparticles of the composition,an interfacial polymerisation of a microemulsion of oil in anaqueous-alcoholic medium is performed by injecting, into an aqueousphase which can contain a surfactant, a mixture consisting of the oil(s)to be encapsulated, at least one (C₂-C₁₂) alkyl cyanoacrylate and atleast one solvent which can contain a surfactant, and then evaporatingoff the solvent.
 14. Process according to claim 13 , in which theaqueous phase contains a surfactant, characterised in that the weightratio of the surfactant used on the one hand, to the materialsconstituting the nanoparticles loaded with active ingredient(s) on theother hand, is between 0.01 and 0.5.
 15. Process for preparing acomposition according to one of claims 1 to 12 , characterised in that,to obtain the nanoparticles of the composition, a mixture containing theoil(s) to be encapsuated, at least one polymer and at least one solventwhich can contain a surfactant is injected into an aqueous phase whichcan contain a surfactant, and the said solvent is then evaportated off.16. Process according to one of claims 13 to 15 , characterised in thata surfactant taken from the group composed of nonionic surfactants,ionic surfactants and mixtures thereof is used.
 17. Process according toclaim 16 , characterised in that the nonionic surfactant is selectedfrom the group composed of the condensates of glycerol, ethylene oxideand propylene oxide.
 18. Process according to claim 16 , characterisedin that a lecithin is selected as an ionic surfactant.